1. Field of the Invention
The present invention relates to a damper disk assembly. More specifically, the present invention relates to a damper disk assembly exhibiting a torque characteristic that has two stages of rigidity.
2. Background Information
A conventional damper mechanism used in a clutch disk assembly of a vehicle has an input rotary member, an output rotary member, and an elastic coupling member. The input rotary member is designed to be coupled to an input flywheel to transfer torque therefrom to the output rotary member. The output rotary member is coupled to a shaft that extends from a transmission. The elastic coupling member elastically couples the input rotary member and the output rotary member together in the rotational direction. The input rotary member has a clutch disk and a pair of input plates fixed to the inside thereof. The output rotary member has a hub that is coupled to the shaft in such a manner that the two cannot rotate relative to each other. The hub has a boss that is splined to the shaft and a flange that extends radially outward from the boss. The elastic coupling mechanism has a plurality of coil springs. Each coil spring is housed inside a window hole formed in the flange and is also supported by corner windows formed in the pair of input plates. When the pair of input plates and the hub rotate relative to each other, the coil springs are compressed between the input plates and hub in a rotational direction. This compressing or damping function serves to absorb and damp torsional vibrations inputted to the clutch disk assembly.
Also known are clutch disk assemblies that use springs of different rigidities to accommodate the various types of vibrations that occur under different traveling conditions. This type of clutch disk assembly achieves a two-stage torsional characteristic. The small coil springs are compressed and a low-rigidity characteristic is obtained when in the region of small twisting angles. Further, the large coil springs are compressed and a high-rigidity characteristic is obtained when in the region of large twisting angles. One known structure for achieving this characteristic is a separated flange type clutch disk assembly in which the flange is independently formed from the hub and the flange and hub are coupled together in the rotational direction by small, low-rigidity coil springs. Also known is an integral type clutch disk assembly in which window holes for large coil springs and window holes for small coil springs are provided in an integral hub flange unit and coil springs are arranged in the window holes.
The separated flange type clutch disk assembly can achieve a wide-angle, low-rigidity torsional characteristic. However, since both a hub and a flange are required, the number of parts is greater than in clutch disk assemblies whose flanges are not separated. Thus, separated flange type clutch disk assemblies have a higher cost.
In the integral type clutch disk assembly, the twisting angle is determined by the rotational angle between the notches in the hub flange and the stop pins arranged in the notches. Furthermore, since four to six large coil springs are arranged in the rotational direction, the notches cannot be made sufficiently large, i.e., a sufficient twisting angle cannot be secured because of the relatively large number of coil springs. Consequently, a small-angle, high-rigidity torsional characteristic is obtained.
In view of the above, there exists a need for a damper disk assembly that overcomes the above mentioned problems in the prior art. This invention addresses this need in the prior art as well as other needs, which will become apparent to those skilled in the art from this disclosure.
An object of the present invention is to provide a damper disk assembly having a simple structure and a wide twisting-angle torsional characteristic.
A damper disk assembly in accordance with a first aspect of the present invention is provided with a hub flange, a pair of first elastic members, a pair of second elastic members, an intermediate rotary member, and a pair of plate members. The hub flange has a boss that can be coupled to a shaft and a flange formed integrally on the outer circumference of the boss. The flange has formed therein a pair of first window holes arranged radially opposite each other and a pair of second window holes arranged radially opposite each other. The two first elastic members are arranged respectively in the pair of first window holes. The two second elastic members have a higher rigidity than the first elastic members and are arranged respectively in the pair of second window holes. The intermediate rotary member couples the first elastic members and the second elastic members together in the rotational direction. The two plate members are arranged on both axially facing sides of the flange and have a support part that supports the second elastic members.
This damper disk assembly uses the pair of second elastic members, which are positioned opposite each other in the radial direction, as the springs for transmitting power and absorbing vibrations when the vehicle is traveling. Consequently, the problem of the limited angle between the stop pins and notches is solved and a wide-twisting angle torsional characteristic can be achieved.
Meanwhile, the two first elastic members, which are arranged in the first window holes of the flange, are used as the springs for absorbing small torsional vibrations during idling. Since the hub flange is a single unitary member, the number of parts does not increase.
A damper disk assembly in accordance with a second aspect of the present invention is a damper disk assembly of the first aspect, wherein the intermediate rotary member has a first member arranged on one axially facing side of the flange and a second member arranged on the opposite axially facing side of the flange. The second member has a protruding part that protrudes toward the first member in the axial direction and engages with the first member such that the two members cannot rotate relative to each other.
In this damper disk assembly, the intermediate rotary member, which couples the pair of first elastic members and the pair of second elastic members in the rotational direction, has two members, a first member and a second member. The second member has a protruding part that engages with the first member. Consequently, conventional sub-pins can be omitted and cost can be reduced by reducing the number of parts.
These and other objects, features, aspects, and advantages of the present invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses a preferred embodiment of the present invention.